


Dear Diary

by kinkyshithere



Category: Shadowhunters (TV)
Genre: Alec is a dirty slut, Alec is kinda soft but also dirty af, Alternate Universe, Anal, Anal Fingering, Anal Play, Blindfolds, Blow Jobs, Bondage, Captivity, Caves, Chains, Costumes, Fluff and Angst, M/M, Magnus is an asshole...or is he?, Masturbation, Nipple Play, Nipple Torture, Sex Magic, Sex Slave Alec Lightwood, Sex Toys, Smut, Stockholm Syndrome, Tentacle Sex, Tentacles, alec is stupid, punishment...kind of
Language: English
Status: In-Progress
Published: 2019-08-26
Updated: 2019-11-01
Packaged: 2020-09-27 00:49:27
Rating: Explicit
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 8
Words: 9,240
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/20398942
Author URL: https://archiveofourown.org/users/kinkyshithere/pseuds/kinkyshithere
Summary: On his way to kill the powerful demon Magnus Bane, Alec Lightwood is getting captured by the demon in his lair. The next 30 days in captivity will not go as Alec expected at all.





	1. Day 1

**Author's Note:**

> I’m also on Twitter: @kinkyshitmalec

**Summary for the Chapter:**

> Alec knew that he shouldn’t have come here all by himself. What was he thinking? But now there was no way back.

Alec knew that he shouldn’t have come here all by himself. What was he thinking? But now there was no way back. He had to go after the mysterious demon to banish him once and for all back to where he came from. When he asked Meliorn if he could lift the Seelie spell that was warding the entrance of the cave, he told him that it would be possible but also that it was impossible for more than one person to enter the cave at the same time. Alec couldn’t have said no. It was his only chance to go after the demon. He didn’t tell his siblings or the other shadowhunters about this mission. They wouldn’t have understood why he had to do this. They would’ve kept him from going in there. And slowly Alec began to realize that they might have been right.

As soon as Alec entered the cave, he noticed that his runes stopped working. He didn’t sign up for this. Meliorn didn’t mention anything about his runes not being able to function down here. But there was no way back now. The only problem was, it was dark as fuck in here and he wasn’t able to activate his Nyx rune to be able to see. He had to slowly walk forward, trying not to trip on anything or getting attacked by anything that could hide in the next corridor or behind the next wall. Alec kept one of his arms on the dark wall next to him to guide his way through the pitch-black underwater cave. At least the cave itself wasn’t filled with water and he was able to breathe properly. As he kept walking, Alec suddenly saw a flashing light at the end of the corridor. That must be it. He must’ve finally made it to the demon’s lair. He tried to walk as silently as possible and he really wished that he could use his soundless rune but, well, he couldn’t.

Alec kept moving forward slowly, his hand still on the corridor’s wall to guide him when he suddenly stopped on the spot. The dry wall he was touching seconds ago suddenly felt different. His hand was covered with a sticky, slimy substance now which was oozing from the wall. Hoping that the slime wasn’t poisonous, he continued walking towards the light, avoiding touching the wall again. As the light turned brighter and brighter, he didn’t need the assurance of the wall anyway as he could clearly see the end of the corridor now which lead into an enormous hall. Carefully, he walked inside the hall, trying not to make any noise when he saw a man standing in front of a wall, his back facing Alec. Was that the powerful demon everyone was so afraid of? He clearly didn’t look the part. However, Alec knew that demons can use glamours to look more like a human and to hide their true face, so he had to be careful. He moved his hand to his quiver to get his bow ready to attack when the demon quickly turned around and restrained his arms with magic.

“Well, well, what do we have here?”, the demon teased. “I haven’t seen a shadowhunter in a long, long time. And such a handsome one, too.”

The demon started circling Alec to take a closer look at him.

“What an exquisite specimen you are, I already have a lot of ideas about what I can do with you.”

Alec tried to move but his whole body was stunned by the demon’s magic. He was totally helpless and at the demon’s mercy. After circling Alec another time, the demon finally came to a halt and raised his hand to touch Alec’s face.

“Please excuse me, I’ve been very rude and forgot to introduce myself. My name is Magnus Bane. Welcome to my lair.”

With that said, the demon snapped his finger and Alec found himself in shackles, chained up against one of the walls.


	2. Day 2

**Summary for the Chapter:**

> “What kind of punishment? Will you let me go after?”
> 
> “We’ll see about that.”, Magnus replied as he was moving closer to Alec. “How about we make a deal, sweetheart?”, he whispered in his ear seductively.

Alec woke up the next morning, his hands and legs still chained to the wall of the demon’s lair. Was it even morning? There was no way to know. He couldn’t even remember when he fell asleep. The demon must’ve sedated him somehow because there is no way Alec could’ve fallen asleep in these circumstances all by himself. He moved his arm and realized that the magic that has prevented him from moving yesterday was gone. And even better, the demon was nowhere to be seen. This was his chance to get out of here, but there was no way he would get out of these shackles without his stele and an unlock rune. He was pulling at the chain that was hooked into the wall behind him. There had to be a way to get out of these. But no matter how hard he pulled, the hooks in the wall didn’t even move a millimeter.

“And what do you think you’re doing?”

Alec jumped a little. The demon was back. Or did he ever leave? It didn’t matter anyway. He had missed his chance to escape this hellhole. A thousand thought crossed Alec’s mind. Will he ever be able to make it out of here alive? What did the demon mean by doing things with him? Will he torture him? He didn’t even want to think about it.

“Let me go, demon!”, he yelled at Magnus.

“Well, why so rude? I told you my name. Don’t shadowhunters have any manners these days?”

“Not towards evil demons who don’t have the right to be here. What is this whole glamour anyway? Do you think you can seduce mortals with a pretty face? Show me your true form!”

“I hate to break it to you, but first, you entered my lair uninvited, so the only one who hasn’t the right to be here is you, and second, this is my true face. Well, at least 90% of it. It’s not my fault that I’m incredibly handsome, you know?”

Alec realized that he didn’t do any good with being rude to the demon. So, he had to change his tactics.

“What do you want? Magnus, was it?”

“The one and only. And mhhh…what do I want? Let me see. You broke into my lair and tried to kill me. That wasn’t really nice of you. So, I guess you need to be punished for your misbehavior to teach you a lesson.”

“What kind of punishment? Will you let me go after?”

“We’ll see about that.”, Magnus replied as he was moving closer to Alec. “How about we make a deal, sweetheart?”, he whispered in his ear seductively.

Alec tried to move away from the demon, but his fetters made it nearly impossible to escape him. A deal? A deal wasn’t too bad if he was getting out of there alive. But it depended on what kind of deal. This was a demon he was dealing with after all and they know their tricks. He had to be clever about this. He couldn’t let the demon win.  
“What do you have in mind?”

“You want to get out of here, do you? And you want me gone apparently, even if I have no clue what I’ve ever done to you. So, what do you say, I keep you here for a month as my slave and I can do whatever I like with you? Killing excluded obviously. After that, I’ll go back to Edom forever and you can go home. Deal?”

Alec swallowed. Whatever he wants? What did he mean by that? Torture? Sex stuff? He had no idea what kind of wicked ideas were going through that demon’s head. Alec had tried a lot of kinky stuff in the past. Mostly with his ex-boyfriend Ryan who was really into BDSM and over time, Alec got really into it, too. However, he had never done it with a demon before. How does that even work? Did he really want to find out? He had to admit that he was a bit curious. Especially because the demon was handsome as fuck. When he came here, he was expecting an ugly, appalling creature. Not this. The fact that the demon told him that this is only 90% of his true form scared him though. What was the other 10%?

“Whatever you want? That’s a bit vague for a deal, don’t you think?”, Alec finally answered.

“I’m not so sure of it myself yet. Whatever I feel like at that moment. But don’t worry, I would never put a scratch on that godlike face of yours.”

“Will that include intimate stuff? I don’t know about that.”

“It might. Why not? Are you a virgin? Or just a prude?”

“None of this. I…I just never have done it with a demon. How does this even work?”

“Oh, you’re adorable. How do you think warlocks are conceived? Trust me, you can find everything that you have your exquisite body on mine, too. So, do we have a deal?”

“I guess.”

“I will need clear consent from you. Is it a yes or is it a no?”

“Yes. Fine. But after all of this, you’ll let me go. And you will leave this dimension and never come back.”

With that said, Magnus snapped his fingers and Alec noticed his change of clothes. Alec wasn’t wearing a shirt anymore and only a loincloth covered his best bits. He was, however, still chained to the wall. He was still completely at Magnus’ mercy, but the strange part was, that he was kind of into it.

Magnus snapped his fingers again and a chair popped up in front of Alec. He sat down and eyed Alec for at least ten minutes. It might have been even longer but the lack of daylight in here made Alec lose track of time.

“What are you doing?”, Alec asked, unsure what the demon had in store for him next.

“I’m still debating about that.”, Magnus answered.

“Will you ever show me your whole true form?”, Alec inquired.

“Oh honey, you’re not ready for that just yet. But when you are, there’s no way I will hold back anymore.”

Magnus smirked. Did he finally decide what he will do to Alec today? He didn’t move from his chair but raised his hand and blue sparkles exited his fingertips. Suddenly, Alec felt a slight pinch on his nipples. It didn’t hurt. It was kind of pleasant actually.

“Do you like that?”, Magnus teased, slowly upping the amount of pain that was flowing through Alec’s nipples.

Alec’s body was shivering. He wasn’t even able to answer the demon. The pain was still bearable, but he didn’t know for how long Magnus would keep it at that level. Fifteen minutes later, he couldn’t take it anymore. He basically begged the demon to stop but he wouldn’t listen. The only reaction Alec got was an even bigger smirk and a wave of magic that sent painful pulses through his entire chest until he finally passed out in his chains.

“Oh, well, that’s boring.”, the demon mumbled before he got up and disappeared into the darkness of the corridors that lead to his lair.


	3. Day 3

**Summary for the Chapter:**

> The mattress looked very comfortable indeed. But everything looked more comfortable than the cold, hard floor he’d been spending the past two days on. His ass started to get sore and he didn’t know for how long he would be able to sit here anymore.

When Alec woke up, he could still feel the shadow of the pain sitting on his chest. The lair was completely dark, and the demon was nowhere to be seen. Did he get bored with him already? Alec thought that he could handle more pain, but with his angelic power not working in here, it was harder than he thought. However, it could’ve been worse. Maybe Magnus only wanted to test out his boundaries before he decided what to do with him next. Even though he didn’t want to feel this way, Alec was kind of thrilled about the idea of not knowing anything.

Suddenly the room was illuminated, and Alec saw a bed standing in the middle of Magnus’ lair. He turned his head around, but the demon was still nowhere to be seen. Alec was eying the bed from the distance. It was king size and had a large headpiece made out of some kind of metal which was molded into an abstract pattern. There was nothing on it except a mattress and a golden sheet that appeared like it was made from silk. This was odd. He hadn’t seen the demon sleeping for the past day but on the other hand, he passed out on both days not knowing where the demon went at night. Do demons even sleep?

“You’re awake.”, a voice said from the corner of the room. “Did you enjoy your beauty sleep? Not that you need it, in my opinion”, the demon shrugged.

The shadowhunter jumped a bit. He had not heard Magnus coming back to his lair. Had he been there the whole time watching him? Without his Nyx rune working he didn’t see a thing when the lights were turned off.

“Well, thank you, I guess.”, Alec replied. “I don’t want to complain or something but sitting on this cold stone floor with my bare ass isn’t really helping.”

“Good that you mention it. You might have noticed the bed, I brought that in just for you. I might be a demon, but I’m not a monster. Even though I quite enjoy the look of you chained up against my wall.”

Alec’s eyes flicked back to the bed. The mattress looked very comfortable indeed. But everything looked more comfortable than the cold, hard floor he’d been spending the past two days on. His ass started to get sore and he didn’t know for how long he would be able to sit here anymore.

“But before we get you up here, we need to clean you up.”, Magnus added. “I usually like dirty boys, but not in that way.”

Magnus flicked his fingers and a wave of magic hovered over Alec’s whole body until a fresh scent of Indian sandalwood filled the air. He unchained Alec, always keeping a close eye on him in case he got any ideas and made him walk to the bed in the middle of the room. While he was slowly walking towards it, Alec suddenly remembered what he was wearing. While the thin layer of fabric covered his front parts entirely, his bare bottom was on full display. Even though he couldn’t see the demon’s face, he felt his eyes glued to his body which made Alec a bit self-conscious.

“I must say, the view in my lair is especially magnificent today.”, the demon commented shamelessly.

Alec didn’t know how to reply. He hasn’t gotten many compliments about his appearance in his life so far. His last boyfriend Ryan was more into actions than talking, so he quietly sat down on the bed, looked at the demon, expecting his next move.

“No, no. Not like that. Lay down on your stomach.”, Magnus demanded.

And Alec did without protest, knowing exactly that he wouldn’t be able to cover himself up. As soon as he laid down, the creature snapped his fingers and Alec’s hands were chained against the rods of the metal headpiece.

“So, what are you gonna do to me today?”, Alec mumbled into the mattress, barely being able to move. “I hope you don’t make me pass out again, cause it’s kind of exhausting.”

Magnus bit his lip. “Not that you are in any position to make demands, but no. I won’t. I think you will enjoy what I have in store for you today.”

With that said, Alec felt the mattress lower under the weight of the demon and a warm hand was pressed on his right buttcheek. He heard the demon silently mumbling under his breath and the only word he understood was ‘muscles’ when all of a sudden his ass cheeks were spread wide open.

“What are you doing?”

“Oh, I totally forgot to ask.”, Magnus replied. “Are you a top or a bottom?”

“I’ve tried both. I don’t really mind switching. I prefer being able to see though.”

“Where’s the fun in that?”, Magnus teased before he conjured up a black silk cloth and tied it around Alec’s eyes. “Today is all about sensations. You won’t need your eyesight for this.”

Magnus’ hands landed on his ass again until he felt a finger slipping inside of him. It didn’t feel usual, on the contrary. It was perfectly normal. It felt good. A second finger entered his hole, splitting him open. He tried to hold back but a moan exited his mouth. Alec had been single since Ryan moved to South Africa and they mutually decided to split up rather than trying to make long-distance work. He hadn’t felt the intimate touch of another person for quite a while now. He missed this. It just felt so good. Even if it was coming from a dastardly demon who held him captive in a cave.

A third finger slipped in and was stretching his entrance aggressively until he all of a sudden heard a vibrating noise echo through the cave. He didn’t hear the demon opening lube or something, but his hole felt entirely slick now. He probably used his magic again, Alec thought.

“Why did you use your fingers instead of your magic?”, Alec inquired curiously.

“Some things are just better done manually, you know. And now be quiet and let me work.”  
Alec shivered as he felt the vibrator slowly sliding down his spine before Magnus teased his entrance with it. He slowly started pressing the toy against his hole, gradually extending the level of vibration while it slid into him further and further. Alec let out another loud groan. Even though he normally preferred the real deal, Magnus’ vibrator still felt so good. He couldn’t quite make out the shape of the toy. He experienced with toys in the past, but this one, this one was something he never felt before and he was enjoying it more than he should. However, if he’s stuck here for a month he might as well get the most out of it.

The vibrator finally hit his prostate and Alec almost screamed out of pleasure, but he bit the mattress instead. His dick was throbbing, but his position felt quite uncomfortable.

“Is it okay if I’m going on my knees for this?”, Alec managed to ask between heavy moans.

“Of course, darling.”

Darling. Why was this demon so friendly? Well, besides the fact that he was holding him hostage in his lair and making him his sex slave. Another thrust of the vibrator threw Alec out of his thoughts. He was kneeling now, cock rock-hard, leaking with pre-come. He wished he could touch himself, make himself come, but the chains around his wrists forbade him to do so.

“C…can I touch myself?”, he moaned while Magnus steadily pushed the toy in and out of his entrance, hitting him exactly in the right spot every time.

“Absolutely not.”, the demon replied. “I want you to come for me without touching yourself, can you do that?”

Magnus increased the speed and intensity of his thrusts.

“Please.”, Alec begged, his cock twitching every time the vibrator hit his prostate.

But Magnus didn’t react to his whining while Alec slowly started to come undone. It only took the demon a few more experienced pushes with the vibrating toy until Alec finally released himself all over the sheets. His body slumped into the mattress in exhaustion. It didn’t take much time and Alec was fast asleep. With a flick of his wrist, Magnus cleaned up the mess, got up from the bed and took a glance at the young, wrecked shadowhunter.

“Good boy.”, he said, and the demon’s lair turned completely dark once more.


	4. Day 4

**Summary for the Chapter:**

> Alec hesitated. He really didn’t know what to expect under the demon’s fancy garments. “Do you just want me to take it off?”, Alec asked, not knowing how to proceed.

When Alec woke up, he still felt the aftermath of last night. He turned around to close his eyes for a few more minutes when he realized that his shackles were gone. Why would Magnus remove his chains when they were the only thing that kept Alec from fleeing his lair? Did the demon become careless all of a sudden? No, Alec thought. He probably had enough wards up to make it impossible for Alec to run.

Suddenly very aware of the fact that he could move freely, even if it was only in between the walls of the lair, Alec sat up and flicked his eyes across the room. Unlike yesterday, the room wasn’t pitch black so he could see everything clearly this time. He turned around to check if Magnus was anywhere to be seen but there was no trace of the demon. Where could he have gone? Alec knew that he hadn’t left the cave for a very long time so he must be somewhere near. Were there other parts in the cave Alec didn’t know about yet?

He turned around again when he saw a piece of paper, some clothes and a feather duster lying at the end of his bed. Well, if you could call a white bowtie and black string clothes anyway. Alec leaned over to grab the piece of paper and started reading it.

_Dearest Alexander,_

_As you might have noticed, I removed your chains. I have some business to attend to, but I will be back later, so don’t get any ideas of running away from me because it wouldn’t work anyway. I cast a spell on my lair which makes it impossible to leave or enter the room if you are not a more powerful demon than me or me myself. So, don’t even try. While I’m gone, I figured you could make yourself useful to earn your room and board, you might say. The lair has become a bit dusty since you’ve been here and to put up the wards took a lot of my energy so I’d thought you could do some cleaning while I’m away. I provided you with an outfit to wear and a feather duster to get rid of all that dirt that is lying around. Like I said, I like it dirty but not in that sense. Take as much time as you need as it could take a while until I’m back. And now as you reached the end of this note, get to work!_

_Magnus_

Was he serious? He had to play his cleaning lady now? Even though it felt wrong to work for his stay, the demon held him hostage here, after all, Alec made a deal. And he was not planning on breaking it. Alec’s eyes went back to the tiny pile of what Magnus had provided for him. He hesitated for a second then grabbed the string and felt the fabric between his fingers. It was soft and shiny silk, it felt way better than what he was wearing at the moment. It also covered a bit more even if it still wasn’t much. He stripped off the leather loincloth and slipped on the black string. The shadowhunter was used to wear boxer briefs and his ass was still a bit sore from last night but it was manageable. He reached for the bowtie and looked at it for a second. This is ridiculous, he thought. He’s not going to wear a fucking bowtie. But he did. He didn’t want to anger Magnus when he comes back. Even though his ‘punishment’ hadn’t been bad at all yet, he was dealing with a powerful demon after all.

Alec tied the bowtie around his neck, picked up the feather duster and started cleaning. Magnus was right. This place was dirty. He continued cleaning and after a while, he lost track of time. There were so many corners and nooks down here, this would take him all day. All of a sudden, he stopped as he felt a warm hand on his buttcheek. He turned around and there he was. Magnus was back. How long was he gone? Alec was so focused on his task that he hadn’t even heard him coming back.

“These fit you wonderfully.”, Magnus commented on the black piece of fabric Alec was wearing. “And you look so adorable with this bowtie.”

“Errm, thanks, I guess.”, Alec replied. “When did you come back? I didn’t hear you.”

“A while ago. But it was such a delight to see you cleaning in this outfit that I didn’t want to interrupt.”, the demon answered.

“So, what made you change your mind?”

“I really needed to touch that delicious ass of yours. I seem to lose control from just the sight of it.”, Magnus sighed.

Alec blushed a bit, taken aback from Magnus’ forwardness. Ryan never gave him compliments on his appearance. He wasn’t used to this.

“I really enjoyed last night. I wanted you to know that.”, Alec said shyly.

Thinking about his still sore ass, he continued. “But I could use a little break, would you mind that? I got all the pleasure yesterday but what about you? I want to make it up to you.”

“Oh Alexander, seeing you come undone is pleasure enough for me. But as you’re asking, what do you have in mind?”

“I don’t really know how the demon body works. If you’d be human, I’d say I suck you off, but I really don’t know how to pleasure a demon. I don’t want to offend you, but do you even have the same parts?”

“Why don’t you come and find out.”, Magnus teased.

Alec hesitated. He really didn’t know what to expect under the demon’s fancy garments. “Do you just want me to take it off?”, Alec asked, not knowing how to proceed.

“Well, you gotta have to put some work in, my dear.”, the demon responded with a smirk.

The young shadowhunter stepped a bit closer and moved his hand to the demon’s belt. He took a deep breath and unbuckled it, before he continued unzipping Magnus’ pants, tearing them down entirely. He let out a gasp. Everything looked perfectly normal. Humanlike. And even better, the demon’s cock was large and gorgeous. The only thing that was a bit off was two transparent patches of skin right on the demon’s hips. Whatever it was, it didn’t bother Alec as he had problems taking his eyes off that beautiful cock in front of him. He couldn’t wait to feel it in his mouth.

“You didn’t expect this, did you?”, Magnus teased again. “I hate to break it to you but a lot of us aren’t too different from you lots.”

Alec didn’t know what to say. After awkwardly eying the demon’s lower body for a while, he stepped forward and kneeled down before he wrapped his hands around Magnus’ cock and started licking the demon’s balls. Magnus let out a moan and grabbed the shadowhunter’s hair.

“Yes, yes, that’s good.”, he mumbled.

Alec continued making his way up to the tip, leaving trails of kisses, sucks, and licks on the length of Magnus’ now rock-hard cock. When he reached the tip, Alec leaned back to stare in the demon’s eyes before he continued licking the pre-come from Magnus’ delicious cock. Then he noticed a slight change. In between moans, Magnus’ eyes had changed. Instead of the deep brown hue, Alec was getting used to in the past 3 days, a pair of golden, catlike eyes stared back at him now. Was this what the demon was hiding? If it was, Alec didn’t know why the demon would hide them from him. They were beautiful. They kind of turned him on even more.

Lust-ridden, the shadowhunter started circling his tongue around the tip of the demon’s cock which resulted in the demon moaning even more.

“Suck me, Alexander. I wanna feel the warmth of your mouth.”, Magnus demanded, reaching for air.

So he did. He had teased enough. He slowly started taking Magnus’ length into his mouth, enjoying the little noises Magnus made, until the demon’s hard cock reached the back of his throat. Alec gagged for a second but the feeling of the smooth, warm cock against his throat felt so good. He started bobbing his head, sucking and licking, letting the demon’s cock push against his throat again and again.

“You’re so good at this.”, the demon panted. “I don’t know if I can hold it any longer.”

Alec hesitated for a second. Do demons come? Will it be safe for him to swallow demon cum? Fuck it, he thought. He wants this. He took Magnus’ full length, going more aggressively now, swirling his tongue around the length and the demon’s tip until he felt Magnus shaking.

“I’m going to come, Alexander. You might want to switch to hands.”, the demon moaned.

But he didn’t, allowing Magnus to pour his release down his throat. Alec licked his lips. The demon’s cum had a sweet taste to it but he hadn’t tasted anything like it before. He got up from his knees and stared at Magnus.

“Was that okay?”, he asked the demon, who still had his eyes closed in euphoria.

Finally, Magnus opened his eyes.

“Enough cleaning for today. You’ve earned yourself a break.”


	5. Day 5

**Summary for the Chapter:**

> Alec leaned back and closed his eyes. And there it was. The image of Magnus’ beautiful leaking dick was right in front of him. He couldn’t get it out of his head no matter how hard he tried.

Alec had been awake for a few hours and was lazily sitting on his mattress. Magnus still hadn’t put his shackles back on but there was also no note today which told him what to do to kill the time. The demon hadn’t been to the lair for quite some time now and Alec was wondering what he might be up to all these times he was just vanishing for hours and hours. Was he plotting something? Doing evil demon stuff? What even is evil demon stuff in Magnus’ case? As far as Alec knew, Magnus hadn’t left this cave in years. But what did it matter anyway? He was not here, and Alec was bored.

He thought about the day before. The young shadowhunter still had a faint taste of Magnus in his mouth and he couldn’t really stop thinking about how much he enjoyed that and how good the demon felt between his lips. He had to get rid of this feeling. He was a shadowhunter. He couldn’t just go around and get his pleasure from a demon. That went against all he stood for. But it felt so goddamn good and no one would know about all of this anyway. He would leave this cave and Magnus would be back in Edom.

Alec leaned back and closed his eyes. And there it was. The image of Magnus’ beautiful leaking dick was right in front of him. He couldn’t get it out of his head no matter how hard he tried. Absent-mindedly his hand went between his legs, his eyes still closed and still picturing the demon’s gorgeous thick cock. He would do anything to feel it inside of him and let Magnus fill him up until he sees stars. His hand wandered underneath the black piece of fabric that was covering him and he took his already half-hard cock in his hand. He started stroking it lightly, thinking about how Magnus would feel inside of him when a quiet moan escaped his mouth. This felt good. And just the thought of the demon’s throbbing cock filling up his hole, pushing against his prostate over and over again railed him up even more. He slowly started intensifying the pace of his strokes, his own cock now rock-hard, already leaking pre-cum.

“So that’s what you’re doing when I’m not around.”, a voice suddenly resonated through the room.

Startled, Alec opened his eyes and took his hands off his leaking cock. Magnus was back and he was leaning against the entrance of the lair, watching the young Shadowhunter.

“You’ve been a very naughty boy, Alexander. This is how you thank me for leaving your shackles off? I think I have to punish you, my dear.”, the demon continued.

“It’s not what you think.”, Alec replied hastily, a blush building up on his neck and face.

“Oh, you’re so cute when you blush. But don’t worry. You might enjoy this.”, Magnus teased with a smirk on his face.

He waved his hands and suddenly the bed was gone leaving Alec lying on the cold stone floor, his hands now bound with a black cloth. While he was still stunned by the sudden change, the demon slowly started walking towards Alec until he suddenly stopped right next to the shadowhunter, looking down at him.

“Didn’t your mother teach you that you shouldn’t touch yourself inappropriately? I cannot tolerate this kind of behavior”, Magnus chuckled, putting his foot on Alec’s chest, slowly increasing the pressure.

“Please.”, Alec begged before the demon shushed him.

The demon took his foot off Alec’s chest, leaned down and whispered into the shadowhunter’s ear: “Let me see what kind of dirty, dirty things were going through your mind.”

He put his hand on Alec’s forehead and closed his eyes, quietly chanting words in a language Alec has never heard of until his eyes suddenly opened again.

“Oh.”, Magnus mumbled. “I can definitely work with that.”

Alec’s eyes widened. Did he just read his mind? He closed his eyes in embarrassment, his cock still throbbing in his underwear, but he couldn’t look at the demon.

“Hey! Look at me!”, the demon demanded, but Alec didn’t dare to open his eyes.

He suddenly felt a warm breath on his chest, followed by a wet tongue licking down from his chest towards his crotch and up again.

“Will you look at me now?”, Magnus asked.

Alec opened his eyes and the demon was now hovering over him, staring him directly into his soul. He couldn’t say that he didn’t like having the creature so close to his own body. From this distance, he could see all of the demon’s features. His dark brown eyes were perfectly lined with black eyeliner. The little specks of glitter running through his hair. The little spot right above his right eyebrow. He was beautiful. He didn’t resemble an evil demonic creature at all. And Alec wanted him even more than before.

“You’re beautiful.”, he whispered.

“What was that?”, the demon replied.

“Are you sure you’re a demon?”, Alec said in a louder voice. “Demons don’t look like that.”

“Like what?”

“Like a god.”, Alec blurted out, suddenly blushing again.

“Is that so?”, Magnus smirked. “Well, let me show you what _that god_ can do.”

The demon snapped his fingers and his and the shadowhunter’s clothes were gone entirely. Alec gasped a little as he hadn’t seen him with his shirt off yet and it only confirmed what he just said.

“Kiss me.”, Alec muttered shyly.  
“This was supposed to be your punishment.”, the demon chuckled before he pressed his lips onto the shadowhunters mouth.

Leaving him with just a teasing peck, Magnus continued to press little kisses down his chest until he reached Alec’s still hard and leaking cock. Alec moaned when he felt Magnus’ warm and wet tongue teasing his balls but then going down his inner thighs leaving his cock untouched.

“I want you inside of me.”, Alec exclaimed, and Magnus didn’t hesitate, snapped his fingers to prepare Alec, flipped him around, pushed his cock into Alec’s hole and hit his prostate so hard that the shadowhunter started seeing stars. Just like he imagined it earlier.

“You feel so good.”, Alec screamed. “Go harder.”

Magnus increased the pace of his thrusts, clawing into Alec’s butt cheeks, moaning in pleasure until he abruptly stopped, flipping Alec around again.

“I want you to ride me.”, he ordered Alec. “I need to see your gorgeous face when you come undone.”

The demon lay down on the cold floor, letting Alec climb on him. He adjusted himself over Magnus’ beautiful, already leaking cock and sat down on it with a hard moan as the demon’s length hit his prostate again. He slid his hands over Magnus’ smooth and muscular chest and started rocking on his dick as if there was no tomorrow.

Magnus didn’t even have to do anything. The feeling of his big hard cock inside of him would be enough to make Alec come in a heartbeat. He suddenly felt a pleasuring warmth inside of him as the demon filled him up with his cum which finally tipped Alec over the edge, too and he spilled his release all over Magnus’ chest before he collapsed on him riding out his orgasm.

All of a sudden, Alec felt a hand on his shoulder and Magnus pushed the shadowhunter off him and got up.

“I don’t do cuddling.”, he said and walked away, leaving Alec on the floor.


	6. Day 6

**Summary for the Chapter:**

> Alec made his way to the lair’s entrance. What would happen if he would just stick a finger through the doorway? He had to try. He stopped in front of the entrance but made sure he kept his distance at an arm’s length. He let out a silent sigh and slowly raised his left arm, holding out his pinkie as he figured that he could live without it in case the wards will do any damage to it.

Alec slept longer than usual. At least it felt like that. Couldn’t Magnus at least leave him a clock, so he’d know what time of day it actually is? The lair was empty as usual, Magnus was nowhere to be seen. Just a thin thread of light was shining through the doorway that leads from the demon’s main hall back to the cave Alec came from. The light caught his attention, he’d never seen it before, but he wouldn’t dare to look for the source of it unless he wanted Magnus’ wards to fry him.

He slowly got up from the cold stone floor, stretching his body. Magnus didn’t bother to get the bed back after he left him there the previous day, but his bonds were gone at least. Sometimes Alec wondered if the demon is really as cold as he pretends to be. When he’s looking into his eyes, he saw a softness which made him think that there must be more behind the façade that Magnus is trying to put on. But he could be wrong.

Still attracted to the light, Alec made his way to the lair’s entrance. What would happen if he would just stick a finger through the doorway? He had to try. He stopped in front of the entrance but made sure he kept his distance at an arm’s length. He let out a silent sigh and slowly raised his left arm, holding out his pinkie as he figured that he could live without it in case the wards will do any damage to it. But nothing happened. Did Magnus forget to put up the wards or did he lie to him about putting them up in the first place?

Alec carefully took a step in the corridor that leads to the cave. And again, nothing happened. The light left an illuminating trail through the corridor and he decided to follow it. After a few steps, he realized that this wasn’t the same way he came from when he went looking for the demon. What will await him down here? How big is this cave actually? He just hoped he didn’t get lost.

He followed the trail until another entrance, which seemed to be the source of the light, was in front of him. He stepped forward and was suddenly standing in another big hall with a big sparkling lake in the middle of it. And in its center was Magnus, standing in the water, only his upper body exposed. His back was facing Alec, shiny drops of water running down his spine. He didn’t seem to have noticed Alec’s arrival as he didn’t turn around or, in fact, move at all.

Alec stepped closer to get a better look at the demon. What was he doing there? Just bathing? Was this where he went all day when he was not present in his lair? Every time he came back to his quarters it didn’t seem at all that he has been bathing or been near any kind of water before, Alec thought. Silently, Alec moved closer to the lake, hoping Magnus wouldn’t notice him. The hard muscles on the demon’s back twitched a bit and Alec held his breath, but the creature still didn’t turn.

Now that Alec was close enough to see everything that was going on, he noticed that Magnus’ body was surrounded by tiny waves. Was he doing some kind of demonic ritual down here? The young shadowhunter had read about all kinds of demonic rituals in the Institute’s library but he’d never heard about anything like what was going on here. Hell, he didn’t even know what he was actually watching. The waves around the demon’s body were intensifying and Alec caught a glimpse of some glittery flesh that seemed to be moving towards Magnus. Were there sea creatures in here? And what would they do to Magnus? Was it safe for him being in this lake?

“Watch out, Magnus!” Alec yelled all of a sudden, trying to warn the demon of the approaching underwater creatures.

Alarmed by Alec’s outcry, the demon turned around and stared at him, his eyes switching from surprise to anger, and the waves and creatures vanished.

“Who allowed you to leave the lair?” he snapped at Alec.

“I’m sorry. I know that wasn’t part of the deal. But I saw that light and then there were no wards and I got kind of curious. Then I saw you in here and it looked like you were getting attacked and…I don’t know. I’m sorry. I didn’t want to anger you,” the shadowhunter responded anxiously.

Magnus’ eyes relaxed. “Well, it can get quite boring in there, I’ll give you that. Even more when I haven’t given you anything to do. But as you’re already here, you might as well come in,” the demon said.

“What about these creatures?” Alec asked nervously. “Is it safe for me to come in?”

“Don’t worry about that. It’ll be perfectly fine,” Magnus calmly responded.

Aware of the fact that he didn’t know what will expect him in these waters, Alec carefully took slow steps into the lake until his lower body was completely submerged into the water. The water was cool and refreshing and after being magically cleaned by Magnus for the past days it was a welcome change.

“Don’t be shy. Come here,” Magnus demanded.

Alec obeyed and made his way towards the middle of the lake where the demon was standing in all his glory, his torso unclothed and exposed to the sparkling light which seemed to reflect off the cave’s walls and draped around him in a way that was flattering all his already gorgeous features.

“What were those creatures?” the young shadowhunter askes curiously. “And where did they go?”

When he finally was standing in front of the demon, he suddenly realized that they weren’t gone. They were draped around Magnus’ hips and legs but weren’t moving at all. Puzzled, he stretched out his arm, trying to reach for them.

“Don’t touch them!” the demon hissed.

But Alec couldn’t stop his curiosity, reached out and felt the rubbery skin and slightly slimy suckers under his fingers.

“Are these tentacles?” he exclaimed in surprise and dug in even further until he realized that it wasn’t, in fact, and individual creature but that they were actually attached to Magnus’ hips at the same spot where he saw the transparent patches of skin a few days ago.  
The tentacles wriggled under his touch. “I told you not to touch them!” Magnus shouted at him.

Magnus’ gaze changed to fury and the tentacles surrounding him shot up and wrapped around the shadowhunters neck. There was a slight sheen to the demon’s eyes. Was he tearing up? Alec couldn’t breathe but the demon kept increasing the pressure around his neck. And suddenly, the world around him turned black.


	7. Day 7

**Summary for the Chapter:**

> “Don’t come any closer,” Magnus hissed, his eyes still glued to the pages in front of him.
> 
> Alec came to a halt, unsure what the demon would do if he came any closer. “What happened yesterday?” he asked. “Was any of this real?”

When Alec opened his eyes, he was chained to the same wall again as he was when Magnus took him prisoner a few days ago. What just happened? Was any of what he saw in the lake real or was it just a feverish dream? Alec didn’t know. The only thing he knew was that he blacked out in the middle of a lake and woke up again in the demon’s lair, once again in shackles.

Right at this moment, Magnus walked into the lair, avoiding Alec’s gaze entirely and made his way to a shelf at the back of the room where he picked up a book and sat down in a chair staring absentmindedly at the pages.

“Hey!” Alec said, but the demon didn’t move.

“I said hey,” the shadowhunter kept pressing. “What’s going on? I thought we were over the whole chained to the wall thing. Can we at least talk about what happened?”

Still not looking at Alec, Magnus moved his hands and the fetters around Alec’s wrists disappeared, leaving the young shadowhunter speechless. Rubbing his sore neck, Alec slowly got up and made a move towards the demon’s chair.

“Don’t come any closer,” Magnus hissed, his eyes still glued to the pages in front of him.

Alec came to a halt, unsure what the demon would do if he came any closer. “What happened yesterday?” he asked. “Was any of this real?”

“I told you not to leave the lair and you disobeyed me.”

“That doesn’t answer my question.”

Magnus dropped the book on the stone floor, lifted his head, and stared Alec straight into his eyes, his face set in anger, which made the shadowhunter shiver a bit.

“You have no right to ask any questions. You are my prisoner. You…you weren’t supposed to see me like that,” Magnus stuttered.

“So, it was real,” Alec whispered to himself before he carefully took another step in the demon’s direction. “Was that the 10% you were talking about?” he asked Magnus. “The tentacles. Are they a part of you?”

“You weren’t supposed to see them,” the demon whimpered before he lowered his head again pressing his face into his hands.

Alec rushed to his side and put a hand to his shoulder. “Hey, look at me,” he said.

“I told you not to come closer,” Magnus muffled in his hands but didn’t resist against Alec’s touch.

“What is it? What’s wrong?” Alec asked, moving his hand under the demon’s chin to make him look at him.

“Well, you saw it. You saw all of me. And you’re still asking what’s wrong? I’m an abomination,” Magnus answered, his eyes becoming shiny as tears are building up in them before he lowered his head again to escape Alec’s gaze.

“Hey.” Alec tipped his chin up again and moved his hands to the demon’s cheek and looked him straight into his eyes. “You’re not an abomination. You’re beautiful.”

A single tear rolled down Magnus’ right cheek. “You don’t mean that. You’ve seen what I am. You’re just saying that because you’re my prisoner and you’re afraid of me. I’m sorry that I hurt you. I really am. I shouldn’t have lashed out, but I panicked.”

“I meant that. And you didn’t hurt me. Well, not much. I’m usually used to more,” the shadowhunter quickly replied. “Can you show me?”

“I can’t.”

“Why? Magnus, you don’t have to be afraid,” Alec tried to reassure the demon.

“I can’t. Not in here anyway.” He turned his face away.

“What do you mean?” the shadowhunter asked curiously, his eyes set in concern.

Magnus let out a deep sigh. “They only work in water. In fact, they only work in special water. So even if I would want to show them to you, I can’t do it in here.”

Alec’s eyes widened. “What do you mean by special water?”

“You’ve seen the cave with the lake,” the demon answered quietly. “It’s not a usual lake. The water contains particles from Edom. I only can show my true, my whole form in there. I have to go there every single day to let them spread or it’ll kill me. That’s why I haven’t left this goddamn cave in years. It’s a curse. A curse my father gave me for leaving Edom. I couldn’t stand it there. I couldn’t stand him. The things he did there…all this pain and torture. I had to escape. But he made well sure that I’ll regret it sooner or later.”

Alec sighed. He didn’t know what to say. He always thought that the demon was one of the deadliest and evilest creatures in this dimension. Maybe he was deadly, but the longer he stayed down here, the more he realized that Magnus wasn’t evil at all. He might have tried to hide it by putting up this act all this time, but Alec had seen it in his eyes very early on. There was a gentleness in them that no pure evil creature could have. And this confession only assured him that there was more behind that cold façade that the demon put on every day.

“So, you weren’t born with the tentacles?” Alec asked gently.

“No, I wasn’t,” Magnus responded. “While I was running, my father struck me with a flash of magic. I didn’t feel anything at first, so I didn’t think much about it, but when I arrived in this world, ready to begin a new, normal life, I soon realized that something had changed in me. I saw the patches on my hips, but I didn’t know what they meant. Until I grew weaker and weaker every day. If the Seelie Queen wouldn’t have found me, I don’t know if I’d still be alive today. They wanted to send me back to Edom at first because they couldn’t find a cure for my illness. It just got worse and worse, but I told them I’d rather die than go back to my father’s palace. And one day, they heard a rumor about this cave and the lake, so they brought me here and it worked. I entered the water, the tentacles unfolded, and all of my symptoms were gone.”

Alec listened carefully, not trying to interrupt the demon but there was one thing he needed to know. “So, why did you stay in here? Couldn’t you just come back from time to time?”

“No,” Magnus replied. “I tried. But every time I got out of this cave, my symptoms grew stronger. So, I decided to stay locked up in here. Even if that meant I couldn’t move freely. But there was no way I would go back to that horrible place I used to call home.”

Alec lowered his head. “I’m so sorry, Magnus. I didn’t know. Is there nothing that can be done to rid you of that curse?”

“Not that I know of. I’ve read so many books trying to find a curse. But I’ve found no answers yet,” Magnus replied, another tear rolling down his face.

The shadowhunter wiped away the tear and took Magnus in a long embrace. “Maybe I can help you find a cure.”

“I’ve been looking for years, Alexander. I don’t think there is one.”

“We can still try. Don’t give up so easily,” Alec replied. “Why don’t we start by you showing them to me again. Maybe I can see something you haven’t.”

“Fine,” the demon said. “But not today. I’ve already been to the lake and I really don’t want to go a second time. We’ll do it tomorrow, ok?”

“Okay. I understand. But no choking this time.”

“I’ll try.”

“And Magnus?”

“Yes?”

“No more chains. And I want you to spend the night with me, no more disappearing.”

Magnus silently nodded and snapped his finger. The bed reappeared and Alec got up and held his hand out for Magnus to follow him. They both laid down facing each other when Alec took Magnus’ cheek in his hand again.

“You don’t have to be afraid anymore. I’m here now,” Alec whispered which made the demon smile before they fell asleep, holding each other tightly.


	8. Day 8, Part 1

**Summary for the Chapter:**

> “Shit, what time is it?” Magnus blurted out and jumped out of the bed, leaving Alec in confusion.
> 
> “Erm…I don’t know, it’s not like you have any clocks down here,” the shadowhunter answered.
> 
> “I have to get to the lake immediately,” the demon urged and made his way to the lair’s exit.
> 
> “Wait! Can I come with you?”

**Notes for the Chapter:**

> Sorry, it's been a while. I've been very busy these past weeks and still am but I'm trying my best to keep this going. Enjoy!

When Alec woke up, he could still feel the heat radiating off Magnus’ body next to him. Since he’d been here, he had never woken up in the demon’s presence. But here he was, lying next to him, still asleep. So that mystery is solved, Alec thought. Demons do sleep. Or at least Magnus does. He kept staring at the beautiful demon. His hair was all messed up from the pillows. Alec had never seen them before like this. He wanted to touch them, so he rose his arm and let his fingers glide through the strands of hair falling into Magnus’ forehead. The demon’s eyes flew open and Alec jumped a bit.

“Shit, what time is it?” Magnus blurted out and jumped out of the bed, leaving Alec in confusion.

“Erm…I don’t know, it’s not like you have any clocks down here,” the shadowhunter answered.

“I have to get to the lake immediately,” the demon urged and made his way to the lair’s exit.

“Wait! Can I come with you?”

“I…I don’t know. Do you really want to?” Magnus inquired. “I have to run though.”

“Give me half a minute.”

Alec got dressed in a hurry and took Magnus by the hand. He still knew the way to the lake, so he dragged the demon along until they reached the second cave. The lake glistening in its glory just like Alec remembered it. He didn't know how urgently Magnus needed to reach the lake and he didn't want to be responsible for any delay. They both stopped at the edge of the water.

"So, what now?" the shadowhunter asked, still holding the demon's hand tightly in his.

"I need to go in. You can wait here," Magnus responded and let go of Alec's hand to snap his fingers and the rest of his clothes disappeared.

Alec stared in awe. Demon or not, Magnus was an exquisite creature.

"Close your mouth, shadowhunter. You're drooling."

Alec snapped out of his bubble and giggled. "Sorry, but the view in here is spectacular."

Magnus laughed and made his way into the water until he reached the middle of the lake. Alec couldn't really see what was going on at first, as the water covered the demon's entire lower body, but the water around Magnus' body began to swirl and glow.

As the current around Magnus grew stronger and stronger, Alec became worried. "Are you okay? Is this normal?"

"Yes, yes. It'll be over in five minutes," the demon yelled from the middle of the lake. "Just hang in there and don't touch the water until I say it's safe."

_Safe?_ Did that mean it wasn't safe? Alec was still worried, but he figured Magnus knew what he was doing. The flow around Magnus' lower body was still growing stronger until a cascade of water surfaced and swallowed the demon entirely. The shadowhunter jumped forward but stopped himself right before his foot hit the water. He almost lost control. What was happening to him? A few weeks ago, he never would've thought that he would be scared for a demon's life. But here we are. It took Alec a lot of willpower to not jump right into the water and drag Magnus out of there. Right at that moment, Magnus emerged back from the water, the area surrounding him still glowing mysteriously. The lake was still now.

"Is it over?" Alec asked.

"Yes, that was it."

"You scared me."

"It's just water, Alexander."

"You told me it wasn't even safe to touch it. Can..can I touch it now? Can I come in?"

"Don't be silly. You've been in here before. Remember? And yes you can. But lose the pants," Magnus smirked.


End file.
